Clearance unloader



Patented Mar. 22, 1927.

N17! 151 ST All AS P 'rsair 0mm FREDERICK VAN 'DUZER LONGIACRE, OIEYONKERS, NEVT "YORK, ASSIGN'OR 'IO INGEB- 'SOLL-RANZD COMPANY, OF JERSEYCITY. NEW JERSEY, A 'CORPORATION 055 NEW JERSEY.

"CLEARANCE UNBOAJDER.

Application filed October 19, 1925. 'Eerial No. 3,308.

The invention relates to compressors, but more particularly to clearanceMH lOQGlGPS, and the primary object of the invention is to obtainclearance control for a compressor by means and devices which avoidaising available valve space.

To accomplish this object 10116 or (more clearance chambers are locatedintermediate the cylinder and the discharge connection, and certain ofthe main discharge valves between the clearance chambers and thecylinder are adapted-to perform the additional function of clearancecontrol valves. Auxiliary discharge valves may be provided between theclearance chamber and the discharge connection, so that when the :maindischarge valves are rendered inoperative for freely opening theclearance chamber to unload the cylinder, the auxiliary valves functionas discharge valves Further objects of the invention will hereinafterappear and the invention is illustrated in the accompanying drawing,which is adiagrammatic longitudinalsectional elevation of so much oi acompressor as will serve to make the invention clear.

Referring to the drawing, the compressor cylinder A is provided with the:recip- :rocating piston 13 and the usual water jacket C. .In thisinstance the compressor is shown as double acting, having the inlet Dand the discharge connection Eada pted to be connected to a suitablereceiver, :not shown. Any suitable or usual inlet valves F, shown inthis instance of the plate type, are provided for eachend of thecylinder, and there may be as many of these valves as necessary ordesirable.

Clearance chambers G and H are located in the cylinder casingintermediate the cylind'er A and the discharge connection E, andsuitable discharge valves J and K, shown in this instance of the platetype, are located in the valve openings L and 0 between the clearancechambers G and H and each end of the cylinder A. Auxiliary dischargevalves P and Q, are provided in the valve openings R and S between theclearance chambers Gr and H and the discharge connection E. Additionaldischarge valves, if desired, may be provided for each end of thecylinder controlling communication between the cylinder and thedischarge connection E, but, for simplicity of illustration, theseadditional discharge valves are not shown.

Suitable means :are provided ztor sends r ing the main discharge valvesJ and K inoperative ior unloading the compressor in one or more steps byreducing the cylinder capacity, and in this instance the valve J isprovided with pressure flu-id means for liftthe entire valve structurefrom'its seat Tin the cylinder while the valve K is shown with ahand-operated means for liiiting the valve from its iseat U in-theicyllinder, and either one oi these devices may :be used, 'as desired. i

A yoke V is connected to the valve J and a piston WV in the cylinder Xis connected by the rod Y to the yoke V, :so that outa ward movement atthe piston WV in the cylinder .X lifts the entire valve structure J fromits seat and renders the valveinoperative, so that the volume of theclearance chamber G is added to thatof one end of the cylinder A torreducing the capacity of the cylinder.

The auxiliary discharge valve -P operating in -conjunction with the maindischarge alve J may also be provided with similar controlling means,comprising the :piston Z in the cylinder :6 connected bythe rod '1) tothe yoke :0, which in turn is connected to the valve structure P.Suitable pressure fluid connections tor the cylinderslX and a n areprovided in the form of pipes (Z and c, which may be controlled manuallyor automatically, :as desired, .and the connections are such that whenpressure fluid-is supplied to the pipes (Z the piston NV od the valve Jwill be actuated inwardly to maintain the valve on its seat so that itfunctions as a main discharge valve, while the piston Z of the auxiliaryvalve P is actuated outwardly to remove the valve P from its seat, andpermit free passage of fluid under pressure from the clearance chamber Gto the discharge connection E. By opening the pipe connection (Z toatmosphere and applying pressure fluid to the pipe connection e,

the relative movement of the pistons W- and Z is reversed and the maindischarge valve J is lifted from its seat and rendered inoperative whilethe auxiliary valve P is returned to its seat and becomes operative tofunction as a discharge valve. In such case the compressor cylinder isunloaded to the extent of the volume of the clearance chamber G. Aplurality of such clearance chambers G may be provided for the same endof the cylinder, as desired, and controlled in the same manner by themain discharge valves.

Hand-operated means are shown in connection with the main dischargevalve K for lifting the valve from its seat, in this instance the yoke7' being connected by a screw threaded stem 9 to the hand or wheel h.The stem 9 co-operates with an internally screw threaded portion 7' ofthe cap or cover la, so that rotation of the stem 9 raises and lowersthe valve structure K. The auxiliary valve Q, is preferably secured infixed position in the valve opening S in any suitable manner and doesnot require mechanism for raising and lowering same, because if desiredthe auxiliary valves P and Q may remain operative at all times.

I claim:

1. In a compressor, the combination of a cylinder and piston, an inletvalve, a dis charge connection, a clearance chamber, a main dischargevalve for discharging the compressed fluid through said clearancechamber to the discharge connection, means for rendering said maindischarge valve inoperative, whereby free communication is affordedbetween the cylinder and clearance chamber for unloading the compressorby reducing the cylinder capacity, and an auxiliary discharge valvebetween the clearance chamber and the said discharge connection.

2. In a compressor, the combination of a cylinder and piston, an inletvalve, a discharge connection, a clearance chamber in termediate thecylinder and said discharge connection, a main discharge valve betweenthe cylinder and said clearance chamber, an auxiliary discharge valvebetween the clearance chamber andthe discharge connection, and means forrendering the main discharge valve inoperative for unloading thecompressor by reducing the cylinder capacity.

3. In a compressor, the combination of a cylinder and piston, an inletvalve,-a discharge connection, a clearance chamber intermediate thecylinder and said discharge connection, a main discharge valve betweenthe cylinder and said clearance chamber, an auxiliary discharge valvebetween the clearance chamber and the discharge connection, and pressurefluid means for automatically rendering the main discharge valveinoperative while permitting the auxiliary discharge valve to functionnormally, thereby unloading the compressor by reducing the cylindercapacity.

4. In a compressor, the combination of a cylinder and piston, an inletvalve, a discharge connection, a clearance chamber intermediate thecylinder and said discharge connection, a main discharge valve betweenthe cylinder and said clearance chamber, an auxiliary discharge valvebetween the clearance chamber and the discharge connection, and meansfor maintaining either one of said valves operative while the other isheld inoperative for loading and unloading the compressor.

5. In a compressor, the combination of a cylinder and piston, an inletvalve, a dis charge connection, a clearance chamber, main and auxiliarydischarge valve structures includin plate valves for discharging thecompressed fluid through said clearance chamber to the dischargeconnection, means for bodily lifting the said main discharge valvestructure from its seat in the cylinder to render the main dischargevalve inoperative while maintaining the auxiliary discharge valvestructure upon its seat, whereby free communication is afi'orded betweenthe-cylinder and clearance chamber for unloading the compressor byreducing the cylinder capacity, and means for also lifting the auxiliarydischarge valve structure from its seat in the clearance chamber tocompletely unload the cylinder.

In testimony whereof I have signed this specification.

FREDERICK van DUZER LONGACRE.

